Working version created and tested

src/DigiSpark_PWM.cpp

@@ -6,35 +6,363 @@
 
 #include "DigiSpark_PWM.h"
 
+// re-import of avr/libraries/ATTinyCore/src/ATTinyCore.h
+// from current dev-version (2.0.0) of ATTinyCore.h https://github.com/SpenceKonde/ATTinyCore
+// also fixing an error in setTimer1Prescaler
+#if defined(__AVR_ATtinyX5__)
+#if !defined(TIMERONE_CLOCK_t)
+#define RE_IMPORT_FROM_2_0_0 true
+typedef enum TIMERONE_CLOCK_enum {
+  TIMER1_FCPU = (0x00),
+  TIMER1_64M_PLL = (0x06),
+  TIMER1_32M_PLL = (0x86)
+} TIMERONE_CLOCK_t;
+
+typedef enum TIMERONE_PRESC_enum {
+  TIMER1_STOPPED = (0x00),
+  TIMER1_DIV1 = (0x01),
+  TIMER1_DIV2 = (0x02),
+  TIMER1_DIV4 = (0x03),
+  TIMER1_DIV8 = (0x04),
+  TIMER1_DIV16 = (0x05),
+  TIMER1_DIV32 = (0x06),
+  TIMER1_DIV64 = (0x07),
+  TIMER1_DIV128 = (0x08),
+  TIMER1_DIV256 = (0x09),
+  TIMER1_DIV512 = (0x0A),
+  TIMER1_DIV1024 = (0x0B),
+  TIMER1_DIV2048 = (0x0C),
+  TIMER1_DIV4096 = (0x0D),
+  TIMER1_DIV8192 = (0x0E),
+  TIMER1_DIV16384 = (0x0F)
+} TIMER1_PRESCALE_t;
+
+void setTimer1Clock(TIMERONE_CLOCK_t clk) {
+  uint8_t t = PLLCSR & 0x87;
+  if ((t & 0x86) == clk) {  // already set right
+    return;
+  }
+
+  uint8_t oldtccr = TCCR1;
+  TCCR1 = oldtccr & 0xF0;
+  if ((clk & 0x04) && ((t & 0x03) != 3)) {
+    // PLL requested and not currently running
+    if (t & 0x02 == 0) {
+      PLLCSR = clk & 0x02;  // enable the PLL
+    }
+    while ((PLLCSR & 0x01) == 0)
+      ;  // Wait for lock
+  }
+  PLLCSR = clk;     // now we can set the PLLCSR.
+  TCCR1 = oldtccr;  // and turn back on the timer.
+}
+
+void setTimer1Prescaler(TIMER1_PRESCALE_t presc) {
+  uint8_t oldtccr = TCCR1;
+  oldtccr &= 0xF0;   // fixed
+  oldtccr |= presc;  // fixed
+  TCCR1 = oldtccr;   // fixed
+}
+
+void setTimer1Top(uint8_t newtop) {
+  OCR1C = newtop;
+}
+
+uint8_t setTimer1Frequency(uint32_t target) {
+  while (true) {
+    uint8_t pll = PLLCSR;
+    pll &= 0x84;
+    unsigned long speed;
+    if (pll == 0x84) {
+// slow asynchronous mode
+#if F_CPU == 16500000
+      speed = 33000000;
+#else
+      speed = 32000000;
+#endif
+    } else if (pll) {
+// fast asynchronous mode
+#if F_CPU == 16500000
+      speed = 66000000;
+#else
+      speed = 64000000;
+#endif
+    } else {
+      // synchronous mode
+      speed = F_CPU;
+    }
+
+    uint32_t topval = speed / target;
+    if (topval < 64 && pll != 0x04) {
+      setTimer1Clock(TIMER1_64M_PLL);
+    } else if (topval < 128 && pll == 0) {
+      setTimer1Clock(TIMER1_32M_PLL);
+    } else {
+      uint8_t newpresc = 1;
+      while ((topval > 255) && (newpresc < 15)) {
+        newpresc++;
+        topval >>= 1;
+      }
+      uint8_t top;
+      if (topval > 255) {
+        top = 255;
+      } else {
+        top = topval;
+      }
+      OCR1C = top;
+      uint8_t tccr = TCCR1;
+      tccr &= 0xF0;
+      tccr |= newpresc;
+      TCCR1 = tccr;
+      return top;
+    }
+  }
+}
+#endif
+#endif
+
+// re-import of ATTinyCore/avr/cores/tiny/wiring_analog.c
+// from current dev-version (2.0.0) of ATTinyCore.h https://github.com/SpenceKonde/ATTinyCore
+// stripped down for ATtiny85
+#if !defined(RE_IMPORT_FROM_2_0_0)
+/// \brief
+/// set duty-cycle of PWM
+/// \details
+/// This is just a wrapper around analogWrite
+/// to set the duty-cycle of PWM by writing the compare register.
+/// Will also connect the pin to the timer.
+/// Pin needs to be on TIMER1. Possible values are:
+/// - PIN_B1 (the onboard LED is connected here)
+/// - PIN_B4
+/// \return
+/// 0 on success, an error otherwise
+uint8_t analogWritePWM(uint8_t pin, int val) {
+  if ((pin != PIN_B1) && (pin != PIN_B4)) {
+    return ERROR_INVALID_PIN;
+  }
+
+  // pass through to analogWrite
+  analogWrite(pin, val);
+
+  // ...and hope that everything went fine...
+  return 0;
+}
+#else
+/// \brief
+/// set duty-cycle of PWM
+/// \details
+/// This is a modified re-import of analogWrite from the current ATTinyCore
+/// Sets duty-cycle of PWM by writing the compare register.
+/// Will also connect the pin to the timer.
+/// Pin needs to be on TIMER1. Possible values are:
+/// - PIN_B1 (the onboard LED is connected here)
+/// - PIN_B4
+/// \return
+/// 0 on success, an error otherwise
+uint8_t analogWritePWM(uint8_t pin, int val) {
+
+  if ((pin != PIN_B1) && (pin != PIN_B4)) {
+    return ERROR_INVALID_PIN;
+  }
+
+  // make sure the pin is an output
+  pinMode(pin, OUTPUT);
+
+  uint8_t timer = digitalPinToTimer(pin);
+  if (timer == TIMER1A) {
+    // connect PIN_PB1 to Pulse Width Modulator channel A
+    TCCR1 |= _BV(COM1A1);
+    OCR1A = val;  // set compare register
+  } else if (timer == TIMER1B) {
+    // connect PIN_PB4 to Pulse Width Modulator channel B
+    GTCCR |= _BV(COM1B1);
+    OCR1B = val;  // set compare register
+  } else {
+    // shouldn't happen...
+    return ERROR_INVALID_PIN;
+  }
+
+  // Return without error
+  return 0;
+}
+#endif
+
+
 
 /// \brief
 /// Constructor of DigiSpark_PWM
 /// \details
 /// This creates a DigiSpark_PWM object.
-DigiSpark_PWM::DigiSpark_PWM(USI_TWI& bus, const uint8_t address) {
-  /*..*/
+/// Output of PWM defaults to Pin PB4
+/// Remember to call begin to actually use the PWM
+/// \return
+/// An object of type DigiSpark_PWM
+DigiSpark_PWM::DigiSpark_PWM() {
+  _PWM_initialized = false;
+  _pin = PIN_PB4;
+}
+
+/// \brief
+/// Constructor of DigiSpark_PWM
+/// \details
+/// This creates a DigiSpark_PWM object.
+/// Output of PWM will be mapped to given Pin
+/// Pin needs to be on TIMER1. Possible values are:
+/// - PIN_B1 (the onboard LED is connected here)
+/// - PIN_B4
+/// Remember to call begin to actually use the PWM
+/// \return
+/// An object of type DigiSpark_PWM
+DigiSpark_PWM::DigiSpark_PWM(uint8_t pin) {
+  _PWM_initialized = false;
+  _pin = pin;
+}
+
+/// \brief
+/// get Pin
+/// \details
+/// Get Pin connected to PWM while creating the object
+/// \return
+/// An object of type DigiSpark_PWM
+uint8_t DigiSpark_PWM::getPin() {
+  return _pin;
 }
 
 /// \brief
 /// begin
 /// \details
 /// Initializes the library
-uint8_t DigiSpark_PWM::begin(uint16_t frequency = 25000, uint8_t dutyCyclePercent = 50) {
-  return 0;
+/// Pin needs to be on TIMER1. Possible values are:
+/// - PIN_B1 (the onboard LED is connected here)
+/// - PIN_B4
+/// \return
+/// 0 on success, an error otherwise
+uint8_t DigiSpark_PWM::begin(uint32_t frequency, uint8_t dutyCyclePercent) {
+
+  if ((_pin != PIN_B1) && (_pin != PIN_B4)) {
+    return ERROR_INVALID_PIN;
+  }
+
+  // initialize the Pin
+  // will also disconect the pin from PWM output
+  pinMode(_pin, OUTPUT);
+  digitalWrite(_pin, LOW);
+
+  // save Frequency
+  _frequency = frequency;
+
+  // save requested duty-cycle
+  _dutyCyclePercent = dutyCyclePercent;
+  // check for bounds
+  if (_dutyCyclePercent > 100)
+    _dutyCyclePercent = 100;
+
+  // set frequency for Timer 1
+  _PWM_initialized = true;
+  _TOP_value = setTimer1Frequency(_frequency);
+
+  // enable PWM (channel A or channel B on timer 1)
+  uint8_t timer = digitalPinToTimer(_pin);
+  if (timer == TIMER1A) {
+
+    // enable Pulse Width Modulator channel A,
+    // leave PIN_PB1 unconnected (will be connected in analogWrite)
+    // set CTC1 to 1 to Clear Timer/Counter on Compare Match
+    uint8_t tccr = TCCR1;
+    tccr &= 0x0F;
+    tccr |= _BV(CTC1) | _BV(PWM1A);
+    TCCR1 = tccr;
+    // disable channel B
+    GTCCR = 0;
+    // set compare register to zero for now
+    OCR1A = 0;
+  } else if (timer == TIMER1B) {
+
+    // set CTC1 to 1 to Clear Timer/Counter on Compare Match
+    // (will also disable channel A)
+    uint8_t tccr = TCCR1;
+    tccr &= 0x0F;
+    tccr |= _BV(CTC1);
+    TCCR1 = tccr;
+    // enable Pulse Width Modulator channel B
+    // connect PIN_PB4 to Pulse Width Modulator channel B
+    // leave PIN_PB4 unconnected  (will be connected in analogWrite)
+    GTCCR = _BV(PWM1B);
+    // set compare register to zero for now
+    OCR1B = 0;
+  }
+
+  // set duty-cycle and connect pin
+  uint8_t err = 0;
+  if (err = setDutyCycle(_dutyCyclePercent)) {
+    _PWM_initialized = false;
+    return err;
+  } else {
+    return 0;
+  }
 }
 
 /// \brief
 /// setDutyCycle
 /// \details
-/// Initializes the library
-uint8_t DigiSpark_PWM::setDutyCycle(uint8_t dutyCyclePercent = 50) {
-  return 0;
+/// sets the duty cycle gien in percent
+/// \return
+/// 0 on success, an error otherwise
+uint8_t DigiSpark_PWM::setDutyCycle(uint8_t dutyCyclePercent) {
+  if (!_PWM_initialized) {
+    return ERROR_NOT_INITIALIZED;
+  }
+
+  if ((_pin != PIN_B1) && (_pin != PIN_B4)) {
+    return ERROR_INVALID_PIN;
+  }
+
+  // catch border cases
+  if (dutyCyclePercent == 0) {
+    // set pin to LOW, when DC should be 0%
+    // digital write also deactivates PWM
+    digitalWrite(_pin, LOW);
+    _dutyCyclePercent = 0;
+    return 0;
+  } else if (dutyCyclePercent >= 100) {
+    // set pin to HIGH, when DC should be 100%
+    // digital write also deactivates PWM
+    digitalWrite(_pin, HIGH);
+    _dutyCyclePercent = 100;
+    return 0;
+  }
+
+  // map duty-cycle from 0-100% range to compare value
+  uint8_t analogValue;
+  analogValue = map(dutyCyclePercent, 0, 100, 0, _TOP_value);
+
+  // set comapare value via analog write
+  return analogWritePWM(_pin, analogValue);
 }
 
 /// \brief
 /// setFrequency
 /// \details
-/// Initializes the library
-uint8_t DigiSpark_PWM::setFrequency(uint16_t frequency = 25000) {
-  return 0;
+/// sets the frequency given in Hz
+/// \return
+/// 0 on success, an error otherwise
+uint8_t DigiSpark_PWM::setFrequency(uint32_t frequency) {
+  if (!_PWM_initialized)
+    return ERROR_NOT_INITIALIZED;
+
+  if ((_pin != PIN_B1) && (_pin != PIN_B4)) {
+    return ERROR_INVALID_PIN;
+  }
+
+  // save Frequency
+  _frequency = frequency;
+
+  // temporarily deactivate PWM output
+  digitalWrite(_pin, LOW);
+
+  // set new frequency for Timer 1
+  _TOP_value = setTimer1Frequency(_frequency);
+
+  // set duty-cycle (using updated TOP-value)
+  return setDutyCycle(_dutyCyclePercent);
 }